西瓜在育苗过程中,由于外界气候条件多变,加之苗床管理不善,易导致西瓜幼苗不能正常生长,因而出现了许多问题。 1.苗期冻害及预防 西瓜采用冷床育苗,由于无加温设施,在遇到回寒天气时,若保温防寒措施跟不上,幼苗极易遭受冻害。幼苗遭受冻害后,轻者子叶、真叶边缘发白,造成短暂的生长停顿;稍重的真叶干枯,只能保住生长点,使壮苗变成弱苗,导致较长时间缓苗,甚至成为僵苗,生育期推迟;严重时全株受冻,最后变黑枯死。 幼苗受冻程度主要与品种、苗龄、幼苗生长情况、保温措施和发生冻害后的处理方法有关。不同品种之间抗寒性是有差异的,苗期长势强的品种,受冻程度轻,反之则重;长势健壮的幼苗受害轻,瘦弱的受害重;保温措施 Watermelon in the nursery process, due to changing climate conditions outside the world, combined with poor management of the seedbed, easily lead to watermelon seedlings can not grow normally, and thus there have been many problems. 1. Seedling frost damage and prevention Watermelon cold bed nursery, due to no heating facilities, in the face of back to the cold weather, if the insulation measures can not keep warm, the seedlings vulnerable to frost damage. Seedlings suffer from frost damage, the light of the cotyledons, true leaves whitish edge, causing a temporary growth pause; slightly heavier true leaves dry, can only keep growing point, so strong seedlings become weak seedlings, resulting in longer time Huanmiao, or even become Stiff seedlings, delayed fertility; severe cold throughout the plant, the last black dead. Frost degree of seedlings mainly with the variety, seedling age, seedling growth, insulation measures and the occurrence of frost damage after the treatment. Different varieties of cold resistance are different, seedling growing strong varieties, the extent of the cold is light, and vice versa; robust seedlings suffer from light, thin and heavy damage; insulation measures